1. Field of the Invention
The invention relates to a method and system for configuring a database, in particular by splitting data objects. This splitting process is frequently termed FRAGMENTATION in database technology. The invention furthermore relates to a method and system for distributing data objects in a database. This process is frequently termed ALLOCATION in database technology.
2. Description of the Related Art
In order to describe formally the data records in a database, data models were developed which map all data in the database and their inter-relationships. An example of such a semantic, or conceptual, data model is the "Entity Relationship Model" (ERM), A logical data model is derived from the semantic data model. Logical data models are the hierarchical data model, frequently also termed the "tree model", the object-oriented data model and the relational data model. A further distinction is made between centralized databases and distributed databases.
In H. F. Korth and A. Silberschatz: "Database System Concepts", McGraw-Hill, New York, 1986, various database concepts are presented and discussed. In a distributed database the data are stored on different storage means. Generally the data are even stored on different computers at different locations. The various computer systems are interconnected by way of a communications network, and are in contact with each other by various means of communication.
In S. Ceri: "Distributed Databases: Principles and Systems", McGraw-Hill, New York, 1984, and in H. Kudlich: "Verteilte Datenbanken: Systemkonzepte und Produkte", Siemens AG, Berlin, 1992, the principle of distributed databases is presented and various distributed database systems discussed.
In S. Ceri, S. Navathe and G. Wiederhold: "Distribution Design of Logical Database Schemas", IEEE Transactions on Software Engineering, Vol. SE-9, No. 4 (July 1983), Page 487-504, and in S. Ceri, B. Pernici and G. Wiederhold: "Distributed Database Design Methodologies", Proceedings of the IEEE, Vol. 75, No. 5 (May 1987), Page 533-545, suggestions for the design of logical database systems are discussed and design methodologies for distributed databases presented.
In R. Nussdorfer: "DRDA: Verteilte Datenbanken fur heterogene Umgebungen", Datenbank Extra, publ.: U. Parthier: "DB2: Seine Tools, Neuerungen und Moglichkeiten", IT Verlag fur innovative Technologien, Sauerlach, 1993, Page 23-27, the industry standard DRDA for distributed databases is described. The architecture specifies protocols and conventions which permit databases of different manufacturers to be linked.
The transition from the logical database schema to a physical database schema can be understood as a configuration of the database, and is for example performed by a Database Administrator.
In I. Fogg and M. Orlowska: "Valid Unbiased Fragmentation for Distributed Database Design", Computers Math. Applic. (UK), Vol. 25, No. 9, 1993, Page 97-106, various possibilities of fragmentation in distributed databases are presented. Not only horizontal and vertical fragmentation are presented, but also combination forms of those modes of fragmentation.
In J. A. Bakker: "A Semantic Approach to Enforce Correctness of Data Distribution Schemes", The Computer Journal (UK), Vol. 37, No. 7, 1994, Page 561-575, the Structured Query Language (SQL) and two Entity Relationship Models are examined in terms of their usability for data distribution. A new approach based on a semantic metamodel for fragmenting and allocating is described, wherein only two modes of horizontal fragmentation are permitted.
In relational databases the data are stored in the form of relations. The relations can also be seen as tables, wherein the attributes of the relations are frequently represented as columns of the tables.
In "Distributed Relational Database Architecture: Evaluation and Planning Guide", 2nd edition, Doc. No. SC26-4650-01, IBM, San Jose (Calif.), USA, 1993, and "Distributed Relational Database Planning and Design Guide for DB2 Users", Doc. No. GG24-3577, IBM, San Jose (Calif.), USA, 1991, both of which publications can be obtained through the offices of IBM Germany or the IBM Corporation, the architecture of distributed relational databases and design guidelines for distributed relational databases are described.
In Y. Zhang, M. E. Orlowska and R. Colomb: "An Efficient Test for the Validity of Unbiased Hybrid Knowledge Fragmentation in Distributed Databases", International Journal of Software Engineering and Knowledge Engineering (Singapore), Vol. 2, No. 4, 1992. Page 589-609, three modes of fragmentation of relational databases are described.
The progressing globalization of companies, together with the necessity of rationalizing production processes, is increasingly bringing about a reorganization of business processes and a consolidation of information systems.
In H. Heilmann: "Workflow Management: Integration von Organisation und Informationsverarbeitung", HMD, 176, 1994, Page 8-21, a business process is described as a delimitable, often partial process, which leads to the creation or exploitation of business output. In this, the main emphasis of the observation is on the dynamic flow of the process from its initialization through to completion. The term "workflow" is frequently used instead of the term "business process".
In F. Leymann and D. Roller: "Business Process Management with FlowMark", Digest of Papers, Cat. No. 94CG3414-0, Spring COMPCON 94, 1994, Page 230 to 234, the IBM FlowMark workflow management system is described. The possibilities of modeling business processes are presented, and the execution of workflow management is described. The IBM FlowMark product can be acquired through the usual channels from IBM Germany or the IBM Corporation.
Flatter organizational structures, such as those propagated under the term "Lean Management", can only be successfully introduced if the decision-making units have at their disposal all necessary information at the right time. This means that, in information technology, ineffective administrative work and complex and lengthy channels and periods of processing must be eliminated, as must island solutions.
Consequently, many companies are re-engineering their business processes in order to optimize them, are automating their standard business processes to improve their execution, and are attempting to unify their information systems on the basis of uniform and company-wide data models, in order to create ideal conditions in terms of information delivery.
The possibilities of modern databases, such as the IBM Database 2, for distributing the data of a logical database across different physical locations converge here to an excellent degree with the two corporate measures described above and with the global structure of many companies; IBM Database 2 can be acquired through the usual channels from IBM Germany or the IBM Corporation.